1. Field of the Invention
The present invention relates to an ink container, and more particularly, to an ink container with improved ink flow.
2. Description of the Prior Art
Please refer to FIG. 1. FIG. 1 is a sectional view of an ink container 10 according to U.S. Pat. No. 6,042,225. The ink container 10 comprises a housing 12, a print head 16, and an ink chamber 23 that is formed inside the housing 12 and includes a center ink well 22, and two side ink wells 24. Each one of the three ink wells 22, 24 is employed to store ink of one color in a porous member 26 such as a foam, which absorbs ink. The ink container 10 further comprises a center ink pipe 28 and two side ink pipes 32. The center ink pipe 28 fluidly connects the center ink well 22 and the print head 16. The side ink pipe 32 connects the side ink well 24 and the print head 16. A center filter 30 is horizontally installed on a top end of the center ink pipe 28 for filtering ink transmitted from the center ink well 22, and each of two side filters 34 is vertically installed between the side ink well 24 and the corresponding side ink pipe 32 for filtering ink transmitted from the side ink well 24.
Due to a capillary attractive force, ink is kept inside the small hole of the porous member 26 such that the porous member 26 is able to absorb and store ink. This is equivalent to providing negative pressure inside the ink wells 22, 24, and the negative pressure force overcomes gravity acting on the ink, so as to reduce the fluid pressure inside the ink pipes 28,32. This prevents ink from leaking outside the print head, so that the printed document is not contaminated. However, on the other hand, if the capillary attraction is strong, the fluid pressure inside the ink pipes 28, 32 becomes too low to provide enough pressure for ejecting ink from the print head 16, so that print quality is affected. In a worst case, ink is locked in the ink wells 22, 24 and is unable to flow into the ink pipes 28,32.
In other words, the fluid pressure inside the ink pipe 28, 32 must be kept in a proper range, such that ink is ejected from the print head 16 when the print head 16 is printing and ink does not leak outside the print head 16 when the print head 16 is not printing.
According to the prior art, the side ink well 24 has a narrower top end (W3 less than W4), so that the top end of the porous member 26 is compressed more than its bottom end. This gives ink inside the side ink well 24 a trend to be pulled up and such a trend resists ink flowing from the top end to the bottom end.
It is therefore a primary objective of the present invention to provide an ink container that improves ink flow from top to bottom.
In a preferred embodiment, the present invention provides an ink container comprising a housing having two side walls, each side wall having an inner surface, a print head installed at a bottom of the housing for ejecting ink onto a document, and an ink chamber formed inside the housing having two inclined walls for dividing the ink chamber into a center ink well and two side ink wells. The center ink well is formed between the two inclined walls and has a width decreasing from top to bottom, each of the two side ink wells is formed between an inclined wall and a corresponding side wall. The inner surface of at least one of the side walls has a greater inclination than that of the corresponding inclined wall, so that the side ink well formed between the side wall and the inclined wall has a width decreasing from top to bottom.
The present invention further provides an ink container that comprises a housing having two side walls, a print head installed at a bottom of the housing for ejecting ink onto a document, and an ink chamber formed inside the housing having two inclined walls for dividing the ink chamber into a center ink well and two side ink wells. The center ink well is formed between the two inclined walls and has a width decreasing from top to bottom. Each of the two side fluid wells is formed between an inclined wall and a corresponding side wall. The ink container further comprises a porous member positioned inside one of the side fluid wells for absorbing ink, and the porous member has a width increasing from top to bottom.
It is an advantage of the present invention that the bottom end of the porous member is compressed more than the top end, to improve ink flow from top to bottom.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment which is illustrated in the various figures and drawings.